trying to find tutorial on slowing down close up bird footage

I am trying to use Twixtor to slow down some close up bird footage. I have come across a few tutorials, which gives me the general idea how to use the program, but nothing really specific on birds. The problem I'm having is mainly as the wings flap and cross the bird body, it causes the body to warp to match the wings. I've tried to roto the bird and wings frame by frame in keyframes, but I still get a lot of warping. I have Twixtor and Twitor Pro as plug-ins for AE CS4.

Only problem when I cut down sensitivity is that I lose the characteristics Twixtor is producing. I think what I need to do is only apply Twixtor to certain parts of the bird at a time. As the wing sweeps by the body, for example, Twixtor is distorting that part of the body to follow the wing. It doesn't happen for long, but it is an unacceptable distortion. I have tried to isolate parts of the bird that I do not want Twixtor to affect by using this tutorial:

but if I just draw a mask around the areas I want to keep isolated, Twixtor seems to be affecting them anyway so I'm not sure how to get around this.

This is an important project and I don't mind taking time to try and do it right, but I am new to Twixtor and still trying to learn it. I just hoped to have a lot more control over the exact areas I want the program to work on, but so far I seem to have little control even when following the above tutorial.

Thanks, I took a look at the mattes tutorial, but I'm not sure how to create the matte to use with Twixtor. She already has a matte within the tutorial, but doesn't explain how she made it or how it was used within Twixtor.

I have had some success with tracking points, another tutorial she created that was easier to follow. I think a combination of tracking points and mattes might be the answer if I can figure out the mattes in more detail.

1) If you need to understand how to "roto in AE", you can probably find good tutorials at the cow even.

2) If you are asking how to make good mattes that will be useful for AE and find the PRO version tutorials complicated,
There is an example with fingers over someone's face in the sample projects that might helphttp://help.revisionfx.com/tutorial/49/
and another one that will show combine used that could help when you set the display mode to show source.

Without visuals of what you are working on it's difficult to explain, I mean it might be an hummingbird whose wings flap so fast that even if was shot at 300 FPS it wpuld still be just motion blur or it might be an eagle flapping it's wings to lift off and half the eagle body is not visible on next frame as the wing falls back... these are very different issues. The main purpose of mattes is to segment in layer to help the algorithm when it fails to understand the content. As such the tracking splines can also be used in conjonction with matters.

The key for layering the shot is to make the mattes as if they were covering the object even when you don't see it on a frame. If a bird is flapping it's wings sideways, you might need 2 mattes, a matte on top for the wing, a matte for the rest of the body, and the background which will be the inverse of the sum of the two foreground mattes...